myProgramming 👨‍💻

DS-Algo, CP Questions | CS-Core subjects | Notes | Practice | Resources to improve...! 🚀

This repository hosts a list of DS-Algo Questions that I've solved, CS-Core Questions and resources that I have been following, and the handwritten notes I made; To improve my thinking skills to crack the opportunities that come in my way.

In progress: Since Nov 2020 - present.

Table of contents:

• Coding Noob 🐣
• Time to go Pro 🚀
• My_Handwritten-notes
• DS-Algo-Questions
• Author

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Noob

1. Written beginner level codes in Py/Java/C/C++ to get an experience of every language.

Codes in C | Codes in Cpp | Codes in Java | Codes in Python.

2. Learned Git/Github.

3. Finally decided to go with C++ (cpp).

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Pro_Noob

A compiled list of resources that I have been following and questions that I have been practising:

Competitive Coding

• Questions upsolved
• MY CP template

Practised & Learned from Internet

GFG | Hackerrank | Leetcode | Youtube University | Misc

Internship & Placements specific preparation (that I've done)

• CS Core Subjects: DBMS, Networks, OOPS, OS
• Subjective Questions
• Puzzles
• System Design
• DS-Algo (Check the table at bottom for DS Algo Qs. solved)

Others

• Learned something unique
• Off-campus info.
• Competitive Coding Resources
• CS-Core Must Do Questions
• DS-Algo Must Do Questions
• Other resources
• Misc
• Memory Dump of interesting tech stuff

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Notes

Link to my handwritten notes (updated occasionally):

Drive link: link (or) Github repo link: link

(both links host the same notes)

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DS-Algo-Qs

• This section consists of a list of DS-Algo Questions that I have practised for internships/placements:
  
• These questions can be accessed via this path:
  myProgramming/Coding/[IMP] INTERN-PLACEMENTS-PREP/DS-ALGO_QUESTIONS_[SOLVED]/ .
  (Link)
  
• Note: The main ans logic of the question is coded & just pasted in main function, than creating a separate function...!.

Contents:

• Basics
• Arrays
• String
• Linked List
• Stack and Queue
• Trees (BT and BST)
• Heap
• Recursion
• Hashing
• Graph
• Greedy
• Dynamic Programming
• Backtracking
• Bit Magic
• Sorting Algos
• Misc (Others)

Basics

Data Structure	Code
Graph	Check
Linkedlist	Check
Tree	Check

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Arrays

Problem	Link	My Solution
Two numbers with sum closest to 0	Visit	Check
Convert array to zig-zag fashion	Visit	Check
Boolean Matrix	Visit	Check
Chocolate Distribution Problem	Visit	Check
Consecutive 1's not allowed	Visit	Check
Contiguous Subarray with given sum	Visit	Check
Count Inversions	Visit	Check
Count the triplets	Visit	Check
Element with left side smaller and right side greater	Visit	Check
Equilibrium Point	Visit	Check
Find Missing And Repeating	Visit	Check
Kadane's Algorithm	Visit	Check
Kth smallest element	Visit	Check
Largest Number formed from an Array	Visit	Check
Last index of One	Visit	Check
Leaders in an array	Visit	Check
Majority Element	Visit	Check
Maximum Index	Visit	Check
Merge Without Extra Space	Visit	Check
Minimum Platforms	Visit	Check
Missing number in array	Visit	Check
Nuts and Bolts Problem	Visit	Check
Pythagorean Triplet	Visit	Check
Rearrange Array Alternately	Visit	Check
Smallest Positive missing number	Visit	Check
Reverse array in groups	Visit	Check
Sort an array of 0s, 1s and 2s	Visit	Check
Spirally traversing a matrix	Visit	Check
Stock buy and sell	Visit	Check
Trapping Rain Water	Visit	Check
Find All Four Sum Numbers	Visit	Check
Find the Duplicate Number	Visit	Check
Fractional Knapsack	Visit	Check
Max Consecutive Ones	Visit	Check
Merge Intervals	Visit	Check
Next Permutation	Visit	Check
Count all possible paths from top left to bottom right	Visit	Check
Remove Duplicates from Sorted Array	Visit	Check
Reverse Pairs	Visit	Check
Rotate Image	Visit	Check

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String

Problem	Link	My Solution
Check if string is rotated by two places	Visit	Check
Longest Palindrome in a String	Visit	Check
Smallest window in a string containing all the characters of another string	Visit	Check
Permutations of a given string	Visit	Check
Remove All Adjacent Duplicates In String	Visit	Check
Remove Duplicates	Visit	Check
Reverse words in a given string	Visit	Check
Longest Substring Without Repeating Characters	Visit	Check
Anagram	Visit	Check
Longest Prefix Suffix - KMP Algo	Visit	Check
Implement strstr & Rabin Karp Algo	Visit	Check
Roman Number to Integer	Visit	Check

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LinkedList

Problem	Link	My Solution
Construct a Linkedlist	Visit	Check
Implement Queue using Linked List	Visit	Check
Implement Stack using Linked List	Visit	Check
Finding middle element in a linked list	Visit	Check
Pairwise swap elements of a linked list	Visit	Check
Remove loop in Linked List	Visit	Check
Reverse a linked list	Visit	Check
Rotate a Linked List	Visit	Check
Sort a linked list of 0s, 1s and 2s	Visit	Check
Check if the linked list has loop or not (Floyd's Algorithm)	Visit	Check
Add two numbers represented by linked lists	Visit	Check
Check if Linked List is Palindrome	Visit	Check
Flattening a Linked List	Visit	Check
Nth node from end of linked list	Visit	Check
Insert and delete from doubly linkedlist	Visit	Check
Intersection point of two linked lists	Visit	Check
Linked List Cycle II	Visit	Check
Merge two sorted linked lists	Visit	Check
Reverse a Linked List in groups of given size	Visit	Check

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Stack_Queue

Problem	Link	My Solution
First non-repeating character in a stream	Visit	Check
Gas Station (Circular Tour)	Visit	Check
Get minimum element from stack	Visit	Check
Largest Rectangular Area in a Histogram	Visit	Check
LRU Cache	Visit	Check
Maximum of all subarrays of size k	Visit	Check
Given a binary matrix, find the maximum size rectangle binary-sub-matrix with all 1’s	Visit	Check
Special Stack	Visit	Check
Next Greater Element	Visit	Check
Next Greater Element (Right)	Visit	Check
Parenthesis Checker	Visit	Check
Queue using two Stacks	Visit	Check
Rotten Oranges	Visit	Check
Stack using two queues	Visit	Check
Stack using two queues	Visit	Check
Stock Span Problem	Visit	Check

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Trees

(Binary Tree)

Problem	Link	My Solution
Level order traversal (BFS)	Visit	Check
Inorder Traversal (Iterative & Recursive)	Visit	Check
Postorder Traversal (Iterative & Recursive)	Visit	Check
Preorder Traversal (Iterative & Recursive)	Visit	Check
Lowest Common Ancestor in a Binary Tree	Visit	Check
Constructing BT	Visit	Check
Binary Tree to DLL	Visit	Check
Bottom View of Binary Tree (Iterative & Recursive)	Visit	Check
Check for Balanced Tree	Visit	Check
Determine if Two Trees are Identical	Visit	Check
Check if Tree is Isomorphic	Visit	Check
Symmetric Tree	Visit	Check
Count Leaves in Binary Tree	Visit	Check
Diameter of Binary Tree	Visit	Check
Flatten Binary Tree to Linked List	Visit	Check
Height of Binary Tree	Visit	Check
Left View of Binary Tree (Iterative & Recursive)	Visit	Check
Binary Tree Maximum Path Sum	Visit	Check
Mirror Tree	Visit	Check
Serialize and Deserialize a Binary Tree	Visit	Check
Level order traversal in spiral form	Visit	Check
Top View of Binary Tree	Visit	Check
Tree from Postorder and Inorder	Visit	Check
Construct Tree from Inorder & Preorder	Visit	Check
Vertical Traversal of Binary Tree	Visit	Check

(Binary Search Tree)

Problem	Link	My Solution
Constructing a BST	Visit	Check
Lowest Common Ancestor in a BST	Visit	Check
Check for BST	Visit	Check
Floor and Ceil from a BST	Visit	Check
k-th smallest element in BST	Visit	Check
Largest BST	Visit	Check
Find a pair with given target in BST	Visit	Check
Populating Next Right Pointers in Each Node	Visit	Check

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Heap

Problem	Link	My Solution
Heap Sort	Visit	Check
Kth largest element in a stream	Visit	Check
Find median in a stream	Visit	Check
Merge K sorted linked lists	Visit	Check
Find k closest numbers in an unsorted array	Visit	Check
Find k numbers with most occurrences in the given array	Visit	Check
K’th Smallest/Largest Element in Unsorted Array	Visit	Check
Connect n ropes with minimum cost	Visit	Check
Sort a K Sorted (nearly sorted) Array	Visit	Check

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Recursion

Problem	Link	My Solution
Flood fill Algorithm	Visit	Check
Josephus problem	Visit	Check
Number of paths	Visit	Check
Special Keyboard	Visit	Check
Generate all balanced parenthesis	Visit	Check
Combination Sum I	Visit	Check
Combination Sum II	Visit	Check
kth symbol in grammar	Visit	Check
Letter case permutation	Visit	Check
Permutation Sequence	Visit	Check
Permutation with spaces	Visit	Check
Reverse a stack using recursion	Visit	Check
Sort an array recursively	Visit	Check
Subset Sums	Visit	Check

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Hashing

Problem	Link	My Solution
Zero Sum Subarrays	Visit	Check
Find all pairs with a given sum	Visit	Check
Common Elements	Visit	Check
Count distinct elements in every window	Visit	Check
Longest Continuous Increasing Subsequence	Visit	Check
Longest Consecutive Sequence	Visit	Check
Sort an array according to the other	Visit	Check
Sorting Elements of an Array by Frequency	Visit	Check

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Graph

Problem	Link	My Solution
BFS of graph	Visit	Check
DFS of Graph	Visit	Check
Find whether path exist	Visit	Check
Alien Dictionary	Visit	Check
Detect cycle in a directed graph	Visit	Check
Detect cycle in an undirected graph	Visit	Check
Floyd Warshall	Visit	Check
Minimum Swaps to Sort	Visit	Check
Find the number of islands	Visit	Check
Topological sort	Visit	Check
Dijkstra's Algorithm - Shortest Path in Undirected Graph	Visit	Check
Bellman Ford Algorithm - Detect Negative Weight Cycle in Graphs	Visit	Check
Check if it's a Bipartite Graph	Visit	Check
Bridges in Graph (or) Cut Edge	Visit	Check
Disjoint Set - Union By Rank and Path Compression	Visit	Check
Kosaraju's Algorithm for Strongly Connected Components (SCC)	Visit	Check
Kruskal's Algorithm to find MST	Visit	Check
MST Prims Algo	Visit	Check
Shortest Path in Undirected Graph with Unit Weights	Visit	Check
Shortest Path in Directed Acyclic Graph (DAG)	Visit	Check

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Greedy

Problem	Link	My Solution
Activity Selection	Visit	Check
Largest number with given sum	Visit	Check
Maximize Toys	Visit	Check
Minimize the Heights II	Visit	Check
Minimize the sum of product	Visit	Check
N meetings in one room	Visit	Check
Job Sequencing Problem	Visit	Check
Greedy Algorithm to find Minimum number of Coins	Visit	Check

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DP

Problem	Link	My Solution
Box Stacking	Visit	Check
Count number of hops	Visit	Check
Max length chain	Visit	Check
Minimum number of jumps	Visit	Check
Minimum Operations	Visit	Check
0/1 Knapsack Problem (DP)	Visit	Check
0/1 Knapsack Problem (Memoization)	Visit	Check
Count ways to reach the n'th stair	Visit	Check
Get Minimum Squares	Visit	Check
Find length of longest common subsequence & print the subsequence (string)	Visit	Check
Given two strings ‘X’ and ‘Y’, find the length of the longest common substring	Visit	Check
Longest Palindromic Subsequence Length	Visit	Check
Shortest Common Supersequence Length	Visit	Check
Longest Increasing Subsequence	Visit	Check
Coin change problem - I	Visit	Check
Coin change problem - II	Visit	Check
Count number of subset with a given difference / Target Sum	Visit	Check
Count subsets sum with X	Visit	Check
Edit Distance	Visit	Check
Egg dropping problem	Visit	Check
Partition problem	Visit	Check
House Robber	Visit	Check
Longest Repeated Subsequence	Visit	Check
Maximum Product Subarray	Visit	Check
Maximum sum increasing subsequence	Visit	Check
Matrix Chain Multiplication	Visit	Check
Minimum number of deletions to make a string palindrome	Visit	Check
Minimum Path Sum	Visit	Check
Minimum sum partition	Visit	Check
Palindrome partitioning problem	Visit	Check
Printing Shortest Common Supersequence	Visit	Check
Maximize The Cut Segments/ Rod Cutting	Visit	Check
Scrambled String	Visit	Check
Sequence Pattern Matching	Visit	Check
Subset sum problem	Visit	Check
Minimum number of deletions and insertions to transform one string into another	Visit	Check
Knapsack with Duplicate Items/ Unbounded Knapsack	Visit	Check
Weighted Job Scheduling	Visit	Check
Word Break	Visit	Check

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Backtracking

Problem	Link	My Solution
N-Queen Problem	Visit	Check
Word Boggle	Visit	Check
M-Coloring Problem	Visit	Check
Permutations of a given string	Visit	Check
Print all possible paths from top left to bottom right of a mXn matrix	Visit	Check
Rat in a Maze Problem - I	Visit	Check
Sudoku Solver	Visit	Check

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Bit_Magic

Problem	Link	My Solution
BASIC Bit Operations	Visit Page	Check
Find first set bit	Visit	Check
Find the 2 unique numbers from an array where all numbers are repeated twice except the two	Visit	Check
Find number of ones in bits of a number	Visit	Check
Check if no. is power of 2	Visit	Check
Power Set	Visit	Check
Find the unique number from an array where all numbers are repeated THRICE except the unique one	Visit	Check
Find the unique number from an array where all numbers are repeated TWICE except the unique one	Visit	Check

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Sorting_Algos

Problem	Link	My Solution
Bubble Sort	Visit	Check
Counting Sort	Visit	Check
Heap Sort	Visit	Check
Insertion Sort	Visit	Check
Merge Sort	Visit	Check
Quick Sort	Visit	Check
Radix Sort	Visit	Check
Selection Sort	Visit	Check
Shell Sort	Visit	Check

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Misc

Problem	Link	My Solution
Allocate minimum number of pages	Visit	Check
Binary Search	Visit	Check
Given two number x and n, find n-th root of x	Visit	Check
Find the element that appears once in sorted array	Visit	Check
Floor in a Sorted Array	Visit	Check
Median in a row-wise sorted Matrix	Visit	Check
Nth Natural Number	Visit	Check
Find the Rotation Count in Rotated Sorted array	Visit	Check
Search in row wise and column wise sorted array	Visit	Check
Sum of Middle Elements of two sorted arrays	Visit	Check
The Celebrity Problem	Visit	Check
Trailing zeroes in factorial	Visit	Check
Miscellaneous Qs	-	Check

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• Side Note: Github gist to some random questions solved again for practice from Leetcode/GFG/Neetcode, etc. ~ Gist

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Author

• Suraj Verma

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